TNF-α (Tumor necrosis factor-α) is recognized as a cytokine which widely participates in biophylaxis-immune mechanism through inflammation. It is known that prolonged and excessive production of TNF-α is a factor which brings about causes of tissue damage and various diseases. Examples of pathology in which TNF-α participates are many pathology such as arthrorheumatism, systemic lupus erythematosus (SLE), cachexia, acute infectious disease, allergy, pyrexia, anemia and diabetes (Yamazaki, Clinical Immunology, 27, 1270, 1995). It is also reported that TNF-α plays an important role in pathogenesis of rheumatoid arthritis and Crohn's disease, which are autoimmune diseases (Andreas Eigler et al., Immunology Today, 18, 487, 1997).
From these reports, compounds which inhibit or suppress TNF-α production are expected to be effective for treatment of the above-mentioned diseases, and various studies have been done (the above-mentioned literatures: Yamazaki, Clinical Immunology, 27, 1270, 1995, Andreas Eigler et al., Immunology Today, 18, 487, 1997). Recently, it was also reported that metalloprotease, which is a proteolytic enzyme, participates in secretion of TNF-α and metalloprotease inhibitors have important effects on the inhibition of TNF-α production and the like (Published Japanese Translation of PCT No. 508115/1997). Japanese Laid-open Patent Publication Nos. 44533/2000 and 119249/2000 disclose compounds having inhibitory effects of TNF-α production. All of these compounds are urea derivatives having a sulfur atom in side chains.
It is meaningful to search compounds having inhibitory activities of TNF-α production and being useful as therapeutic agents for the autoimmune diseases such as rheumatoid arthritis, allergy and diabetes.